An important aspect of any computer system is power provisioning. Generally, regulated power must be supplied to various system components, such as peripheral devices, circuit boards, and integrated circuits. Under a typical configuration, a power supply is used to convert alternating current (AC) input to various direct current (DC) voltage outputs that are supplied to the computer system. The power supply provides a certain level of power conditioning that is suitable for many of the system components. However, the voltage conditioning provided by the power supply is generally insufficient for powering critical components, such as the system processor(s).
In order to provide enhanced power conditioning, many systems employ a specially-configured voltage regulator or voltage regulation module (VRM). The voltage regulator or VRM receives “pre-conditioned” DC input from the power supply, and further conditions the input to remove transient voltages and the like. This power condition functionality is accomplished by passing the input voltage through various filter components, including passive and/or active filter elements. For a voltage regulator, the voltage regulation components are mounted directly on the motherboard (or other circuit board), while for a VRM the voltage regulation components are mounted to a separate board that is coupled to the motherboard (or other circuit board) via a connector. For many servers, the VRM is a detachable module that is coupled to the motherboard via a connector that employs a built-in locking mechanism to secure the module in place.
A typical voltage regulator mounting scheme is shown in FIG. 1a. Under this example, voltage regulator components 100 are mounted to a motherboard 102. A power supply (not shown) is also coupled to the motherboard 102, and provides input power to voltage regulator components 100 via corresponding power planes/traces formed on the motherboard (also not shown). A processor package 104 is coupled to motherboard 102 via a socket 106. Typically, socket 106 is mounted to motherboard 102 using a solder reflow process, resulting in a plurality of solder connections 108. Generally, socket 106 may comprise a conventional socketed connector or a zero insertion force (ZIF) connector, either of which comprise a plurality of socket connections 109.
Processor package 104 includes a package substrate 110, a processor die 112, an integrated heat spreader (IHS) 114, and a heat sink 116. The underside of processor die 112 is “flip bonded” to package substrate 110 via a plurality of solder balls 118. The topside of the processor die is thermally coupled to IHS 114 via a thermal paste 120. Heat sink 116 will usually be coupled to IHS 114 in a manner that supports excellent heat transfer between the components, such as via a thermal paste 122. These coupling means further include solders and mechanical mounting techniques, such as mounting clips and the like.
An alternative conventional voltage regulator scheme is shown in FIG. 1b. Under this scheme, a VRM 124 comprising voltage regulator components 100A mounted on a circuit board 126 is coupled to motherboard 102 via a connector 128.
The conventional voltage regulator and VRM mounting schemes have several drawbacks. First, since the voltage regulation components or VRM are coupled to the motherboard, it is necessary to route power from the regulated voltage output through the motherboard to the processor. With the ever-increasing processor speeds, a corresponding increase in power consumption has followed. Since the supply voltage (e.g., 3.3 volts) to the processor must remain low, the heat generated via the power traces in the motherboard has increased in parallel with the increase in processor power consumption. This leads to overheating of the motherboard power traces and thermal stresses on solder connections 108 and/or the socket connections.
Other drawbacks relate to mechanical considerations. Typically, VRMs are placed into environments that employ forced convection cooling via one or more fans. The airflow over the VRM and/or other system components may induce mechanical resonances. These resonances may, in turn, be coupled into the connection between the VRM and the motherboard, leading to connection failures.